131 research outputs found
Coxeter categories and quantum groups
No full textWe define the notion of braided Coxeter category, which is informally a monoidal category carrying compatible, commuting actions of a generalised braid group B_W and Artin’s braid groups B_n on the tensor powers of its objects. The data which defines the action of B_W bears a formal similarity to the associativity constraints in a monoidal category, but is related to the coherence of a family of fiber functors. We show that the quantum Weyl group operators of a quantised Kac–Moody algebra U_{\hbar }{{\mathfrak {g}}}, together with the universal R-matrices of its Levi subalgebras, give rise to a braided Coxeter category structure on integrable, category {\mathcal {O}}-modules for U_{\hbar }{{\mathfrak {g}}}. By relying on the 2-categorical extension of Etingof–Kazhdan quantisation obtained in Appel and Toledano Laredo (Selecta Math NS 24:3529–3617, 2018), we then prove that this structure can be transferred to integrable, category {\mathcal {O}}-representations of {\mathfrak {g}}. These results are used in Appel and Toledano Laredo (arXiv:1512.03041, p 48, 2015) to give a monodromic description of the quantum Weyl group operators of U_{\hbar }{{\mathfrak {g}}}, which extends the one obtained by the second author for a semisimple Lie algebra
Fotografía Artística Guerra Escenarios. Num. 13 Año 5 (2001) septiembre-diciembre. Alquimia. Sistema Nacional de Fototecas
No full text- Un acervo para la microhistoria - La fotografía de Pedro Guerra Jordán, por Edward Montañez Pérez - Los fotógrafos contemporáneos de Pedro Guerra Jordán, por Waldemaro Concha Vargas - Thompson en el cenote sagrado, por Jesse Lerner - La sociedad yucateca representada desde la Fotografía Guerra, por José Carlos Magaña Toledano - De lo modesto a lo suntuoso: costumbres funerarias en Yucatán, por Limbergh Herrera Balam - Charla fotográfica, por Pedro Guerra Aguilar - Los tiempos de la fotografía, por Boris Kossoy - La Fototeca Pedro Guerra, por José Carlos Magaña Toledano
Monodromy of the Casimir connection of a symmetrisable Kac-Moody algebra
No full textLet g be a symmetrisable Kac-Moody algebra and V an integrable g-module in
category O. We show that the monodromy of the (normally ordered) rational
Casimir connection on V can be made equivariant with respect to the Weyl group
W of g, and therefore defines an action of the braid group B_W of W on V. We
then prove that this action is canonically equivalent to the quantum Weyl group
action of B_W on a quantum deformation of V, that is an integrable, category
O-module V_h over the quantum group U_h(g) such that V_h/hV_h is isomorphic to
V. This extends a result of the second author which is valid for g semisimple.Comment: Some details added. Minor revisions throughout. Published version.
107 page
Uniqueness of Coxeter structures on Kac–Moody algebras
No full textAbstract. Let g be a symmetrisable Kac–Moody algebra, and Ung the corresponding quantum group. We showed in [1, 2] that the braided Coxeter structure on integrable, category O representations of Ung which underlies the R–matrix actions arising from the Levi subalgebras of Ung and the quantum Weyl group action of the generalised braid group Bg can be transferred to integrable, category O representations of g. We prove in this paper that, up to unique equivalence, there is a unique such structure on the latter category with prescribed restriction functors, R–matrices, and local monodromies. This extends, simplifies and strengthens a similar result of the second author valid when g is semisimple, and is used in [3] to describe the monodromy of the rational Casimir connection of g in terms of the quantum Weyl group operators of Ung. Our main tool is a refinement of Enriquez’s universal algebras, which is adapted to the PROP describing a Lie bialgebra graded by the non–negative roots of g.<br/
"Une étude descriptive démontre l'implication des leucotriènes dans la bronchiolite sévère à virus respiratoire syncytial"
No full textMémoire numérisé par la Direction des bibliothèques de l'Université de Montréal
Un essai clinique avec la diméthylglycine pour le traitement d'enfants porteurs d'un déficit congénital en cytochrome C oxydase de type Saguenay-Lac-Saint-Jean
No full textMémoire numérisé par la Direction des bibliothèques de l'Université de Montréal
Induction de l'apoptose des neutrophiles de nouveau-nés par l'infection au virus herpès simplex-1
No full textMémoire numérisé par la Direction des bibliothèques de l'Université de Montréal
Radical research as research at the roots: Practitioner self-image, public relations and ethics
No full textSemantically, radical derives from ‘radix’, the Latin for root. This paper argues that little public relations research goes back to the roots of actual practice and addresses this neglect through a project focusing on practitioner accounts of their work. When considering public relations ethics, practitioner self-images and cultural values become an essential research component. In addressing this neglected area of research, this paper examines the subjective perceptions of public relations practitioners regarding their role, commitments, and responsibilities within the framework of their specific culture and national history. In considering practitioner testimonials about professional integrity, briefs, and goals, especially as members of the society and nation to which they belong, the paper engages with ethical aspects of the practice from a cultural perspective that assumes different cultures can have different ethical expectations. In revealing the impact of features that are often ‘taken for granted’ in one country, the paper uses the example of four generations of practitioners who served one major institution in Israel to suggest how similar research at the professional roots in other nations might enable knowledge of international similarities and difference in relation to ethics in action
Platelet activating factor's role in regulating apoptosis in immature B cells
No full textB lymphocyte development is characterized by deletion, via apoptosis, of immature cells that are stimulated via the BCR in the absence of a second signal. We have investigated whether platelet-activating factor, a potent B lymphocyte activator, can provide a complementary signal with BCR ligation in order to abrogate apoptosis. Cross-linking of the sIgM on Ramos B lymphoblastoid cells using anti-IgM antibodies (2mug/ml) caused PCD in 34 +/- 5.4% of the cells. Co-incubation of PAF (10-7M) with alphaIgM led to a significant decrease in apoptotic cells as measured by DNA laddering and TUNEL assay (13.8 +/- 3%). The effect of PAF was dose dependent (10-7--10-9M), and was inhibited by the specific PAF receptor antagonist, WEB 2170. PAF protected cells from the effect of alphaIgM for up to one hour after it was added.alphaIgM-induced PCD in Ramos cells is blocked by catalase, and therefore PCD is caused in part by the production of toxic hydroxyl radicals from hydrogen peroxide. We investigated the action of PAF on markers of intracellular oxidation. H2O2 in low doses induced apoptosis, via production of OH· radicals. PAF inhibited H2O2 induced apoptosis in Ramos cells; it also attenuated H2O 2 and alphaIgM-mediated increases in hydroxyl radical (OH· ) as measured by the oxidation of 2',7 '-dichlorofluorescein diacetate (DCFH-DA) to DCF, and blocked the depletion of GSH induced by alphaIgM. PAF maintained IgM secretion, greatly inhibited by incubation with alphaIgM alone
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